Concrete load supporting structure

ABSTRACT

A CONCRETE LOAD SUPPORTING STRUCTURE OF THE TYPE WHICH COMPRISES A PLURALITY OF RELATIVELY SLENDER BEAMS SUPPORTED ON GIRDERS, THESE BEAMS BEING SPACED AND HELD IN PLACE BY SPACER STRIPS WHEREBY THE BEAMS ARE PROTECTED FROM BECOMING BUCKLED UNDER THE INFLUENCE OF A CONCRETE LOAD.

March 2, 1971 YOSHIRO WATANABE 3,566,567

CONCRETE LOAD SUPPORTING STRUCTURE 3 Sheets-Sheet 1 Filed July 25, 1969FIG.

FIG. 2

INVENTOR.

YOSHIRO WATANABE flak 711% ATTORNEYS March 2, 1971 YOSHIRO WATANABECONCRETE LOAD SUPPORTING STRUCTURE Filed July 25, 1969 '3 Sheets-Sheet aE[ fiik 29 26 2o 20 INVEN'IOR.

YOSHIRO WATANABE BY.

W/ffiflfi ATTORNEYS March 1971 YOSHIRO WATANABE 3,

CONCRETE LOAD SUPPORTING STRUCTURE Filed July 25, 1969 3 Sheets-Sheet 3INVEN'I'OR.

YOSHIRO WATANABE ATTOR EYS United States Patent US. Cl. 52-250 3 ClaimsABSTRACT OF THE DISCLOSURE A concrete load supporting structure of thetype which comprises a plurality of relatively slender beams supportedon girders, these beams being spaced and held in place by spacer stripswhereby the beams are protected from becoming buckled under theinfluence of a concrete load.

This invention relates to improvements in and relating to a concreteload supporting structure and has particular reference to a structure ofthe type including open web steel joists.

Conventional concrete load supporting structures relied upon the use ofbeam materials of suflicient mechanical rigidity to withstand downwardpressures of a concrete slab plus weight of concrete applying equipment,and hence such beams were necessarily heavy and costly. Steel beams, iflacking in such mechanical strength, would tend to buckle under theinfluence of concrete load.

Whereas, it is the primary object of this invention to provide novel,useful concrete supporting bed structures of this character which willeliminate the above noted disadvantages of the conventional structuresand which will permit of the use of relatively slender steel beams suchas round bars and the like for supporting a concrete load thereonwithout causing them to buckle or otherwise become deformed.

According to the invention, there is provided a concrete load supportingstructure which includes a framework generally consisting oflongitudinal and transverse wide-flange girders each having a top and abottom flange and a web, said girders being criss-crossed at and carriedon supporting columns, a plurality of latticed beam members extending inparallel with the transverse girders and arranged in a substantiallyparallel spaced-apart relation, each of which members consisting of anupper chord, a lower chord and a latticed chord connected therebetween,and having its ends supported on and secured to the longitudinalgirders, a plurality of spacer strips arranged in a substantiallyparallel spaced-apart relation and in parallel with the longitudinalgirders, each of which strips spanning over and interlinking twoadjacent beam members at points where said latticed chords are hinged tosaid upper chords of the beam members, whereby a supporting bed in acriss-cross pattern is formed, and corrugated sheets laid over the bedand extending substantially at right angles to and in contact with saidspacer strips.

These and other features of the present invention will be betterunderstood from the following description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a plan View partially broken away of the concrete loadsupporting structure embodying the present invention;

FIG. 2 is a transverse cross-sectional view on an enlarged scale takenon line IIII in FIG. 1 with a concrete slab formed in the base;

FIG. 3 is a longitudinal cross-sectional view on an enlarged scale takenon line III-III in FIG. 1;

FIG. 4 is a frontal view on an enlarged scale of a 3,566,567 PatentedMar. 2, 1971 spacer strip for use in the first embodiment shown in FIGS.1 through 3;

FIGS. 5 through 7, inclusive, show a second embodiment;

FIG. 5 showing a view corresponding to FIG. 2; FIG. 6 showing a viewcorresponding to FIG. 3 and FIG. 7 showing a modified spacer strip.

Like numerals refer to like parts throughout the drawings. Reference isfirst had to FIG. 1 which shows a concrete load supporting structuregenerally designated at 10 and considered here as a building floor forpurposes of illustration. This structure generally includes a steelframework consisting of a pair of opposed longitudinal girders 11extending in criss-crossed relation with a pair of opposed transversegirders 12. These pairs of girders are supported on supporting columns13 at as many points of criss-cross as may be required for a particularapplication.

Each girder 11 is an H-shape steel in common use having a top flange 14,a bottom flange 15 and a web 16 as shown in FIGS. 2, 3, 5 and 6.

Designated generally at 17 are a plurality of open Web steel joists orlatticed beam members of a relatively slender steel such as round barseach consisting of an upper chord 18, a lower chord 19 and a latticedchord 20. The latticed chord 20 is hinged for instance by welding as at21 and 22 to the upper and lower chords 18 and 19, respectively. Therespective ends of the upper and lower chords are brought together andsecured via suitable plate members 23 to the longitudinal girders 11 bymeans of welding, so that the latticed beams 17 run in a substantiallyparallel, spaced-apart relation and substantially in parallel with thetransverse girders 12.

Designated at 24 is a spacer strip which in one preferred form assumesthe shape shown in FIG. 4 and which has a straight, horizontal portion25 and inwardly bent, hooked end portions 26. The straight, horizontalportion 25 has a length substantially equal to the spacing or spanbetween adjacent latticed beams 17. Each of these spacer strips 24 spansover and interlinks two adjacent latticed beam members 17, for whichpurpose the hooked end portions 26 are arranged to hook around the upperhinges 21 of the beam members. As illustrated in FIG. 1, a plurality ofspacer strips 24 are arranged in a substantially parallel, spaced-apartrelation, and they intersect the latticed beam members 17 therebyforming a concrete load supporting structure in a criss-cross pattern.It will be noted that the terminating groups of spacer strips 24 haveone end portions devoid of the hooked portions 26 and bent slightlyupward as at 24 in FIG. 3 so that with these end portions secured to thetop flanges of the girders 12, the spacer strips 24 lie substantiallyflush with the top flange surface.

Designated at 27 is a corrugated steel sheet or the like which is laidover the supporting structure 10 and extends substantially at rightangles to and in contact with the spacer strips 24. Over this corrugatedsteel sheet is cast a concrete slab containing therein reinforcing [bars(not illustrated) The concrete load supporting structure thusconstructed according to the invention features the provision of spacerstrips 24 which serves two-fold purposes. Firstly, the spacer striparrangement restricts lateral movement of the latticed beams 17 whichare made of less costly round bars and prevents the latter from bucklingor otherwise becoming deformed when a concrete slab 28 is cast over thesupporting structure. Secondly, since the spacer strips 24 are disposedin contact with the corrugated sheet 27 over which a concrete is cast,they transfer the load of concrete for concentration at the strongerpart of the latticed beam structure, which lies at the upper hinges 21of the beams, thereby avoiding direct load distribution through therelatively weak mid-portions of the upper chords 18 which lie betweenthe hinges 21. It is in this connection important to locate and hook thespacer strips 24 at the upper hinges 21 of the latticed beams 17, forwhich purpose they may be provided if necessary with stopper means 29 asshown in FIG. 4 to prevent lateral movement of the upper chords 18.

Reference to FIGS. 5, 6 and 7, inclusive, shows the second embodiment ofthis invention which is analogous in basic concept to the firstembodiment hereinabove described. The second embodiment offers theadvantage that thickness of a concrete slab for a given designrequirement may be substantially reduced and at the same time, height ofthe resulting floor slab as a whole above the base course may beconsiderably lowered. This advantage accrues from the following concretesupporting structure.

The upper chord 18 of each latticed beam member 17 is provided with anupgrade slope 30 extending along the latticed chord 20, so that with theends of the beam 17 secured on the longitudinal girders 11, the mainhorizontal portion of the beam 17 lies below the level of the top flange14 of the girder 11. These beam members 17 are held in position in amanner similar to the first embodiment by means of a plurality of spacerstrips 24 each having a straight, horizontal portion 25, upright arms 31and hook-like ends 32 as shown in FIG. 7. With each spacer strip 24spanned over two adjacent beam members 17 and its ends 32 hooked aroundthe hinges 21 of the beam members 17, the horizontal portion 25 of thestrip 24 on which the corrugated sheet 27 is laid becomes situated belowthe level of the top flanges of the girders. The terminating groups ofspacer strips 24 have their respective flat ends supported on andsecured to ledges 3 3 projecting from the webs 16 of the transversegirders 12 as seen in FIG. 6. Similar ledges 33' are formed on 'the websof the longitudinal girders 11 for supporting thereon the ends of thecorrugated sheets 27 arranged substantially at right angles to thespacer strips 24 as seen in FIG. 5. As a concrete slab is cast over thecorrugated sheets, the arms 31 and hook portions 32 of the spacer stripsare embedded in the concrete layer so that these portions of the stripslend themselves to the effect of a combined beam with the latticed beammembers 17 and thus augment the load supporting capabilities of theresulting concrete floor.

As is obvious to those skilled in the art, substantial portions of thelatticed Ebeam members 17 as used in the first embodiment illustratedspecifically in FIG. 2 may be removed after the concrete slab is curedand hardened.

It will be understood that the present invention is not limited to theprecise form and arrangements of the concrete load supporting structure,but many modifications and changes may be made therein without departingfrom the scope of the appended claims.

What is claimed is:

1. In a concrete load supporting structure which includes a frameworkgenerally consisting of longitudinal and transverse wide-flange girderseach having a top and a bottom flange and a web, said girders beingcrisscrossed at and carried on supporting columns, a plurality oflatticed beam members extending in parallel with the transverse girdersand arranged in a substantially parallel spaced-apart relation, each ofwhich members 'consisting of an upper chord, a lower chord and alatticed chord connected therebetween, and having its ends supported onand secured to the longitudinal girders, a plurality of spacer stripsarranged in a substantially parallel spaced-apart relation and inparallel with the longitudinal girders, each of which strips spanningover and interlinking two adjacent beam members at points where saidlatticed chords are hinged to said upper chords of the beam members,whereby a supporting bed in a criss-cross pattern is formed, andcorrugated sheets laid over the bed and extending substantially at rightangles to and in contact with said spacer strips.

2. The structure according to claim a1 wherein said spacer strips arearranged substantially flush with the top flanges of the girders.

3. The structure according to claim 1 wherein said spacer strips arearranged below the level of the top flanges of the girders and partlyembedded in the concrete slab.

References Cited UNITED STATES PATENTS 471,772 3/1892 Orr 52-326X644,914 3 1900 Himmelwright 52--326 1,804,132 5/1931 Tashjian 52335X1,982,343 11/1934 Kane 52--252 2,055,701 9/1936 Palmer 52335X 2,191,8282/1940 Bruehlman 52326 FOREIGN PATENTS 990,646 6/1951 France 52-326ALFRED C. PERHAM, Primary Examiner US. Cl. X.R.

